Presently in the art there are available publications that handle the requirement to allow connections between users of IP-based networks and users of non-IP-based networks, such as circuit switched networks.
For example, US 2005/058125 (“IP-based services for circuit-switched networks”, Mutikainen et al., published in 2005) describes a mechanism for providing a connection from an IP-based network to a circuit-switched network, such as a GSM network. A temporary routing number for the circuit-switched network, such as an E.164 number, is delivered to a user terminal, and a circuit-switched call leg is established from the user terminal to the IP-based network using the routing number. Thereby, IMS-services are provided for end users who are located in the radio access network not having sufficient QoS required for voice over IP. In the example of a conference call service, a request for a conference call may be forwarded via a data channel or data path to an application server which provides that conference call service. The application server then selects a conference routing number and returns the routing number to the conference host terminal via the data channel. Using the received conference routing number, the conference host terminal can then set up a circuit-switched connection as a call leg of the conference call.
Another example is ES 2253101 (“Authentication vector (AV) requesting and dispatching method involves generating AV based on type of service, and sending third message containing AV to IMS network”, Ochoa and Sendra, published in 2006), disclosing an HLR that determines if an AV request is from an IMS service, a global system for mobile communications (GSM)/general packet radio service (GPRS) service or universal mobile telecommunication system (UMTS) service. An authentication center in the HLR generates the AV with a key associated with the subscriber identity, IMPI. The HLR sends a third message containing the AV to an IMS network: A first message requesting for the AV to authenticate a subscriber requesting IMS service is received by an HSS through an IMS network. The HSS processes the first message and sends a second message to the HLR.
WO 08075938 (“SCP-Controlled Overlay between GSM and IMS”, Noldus and Terrill, published on 2008) describes a method of executing a service in a Media Gateway Control Function for establishing a call between a calling party's terminal served by a Mobile Switching Centre, and an IP Multimedia Subsystem Service. The Media Gateway Control Function is arranged to query a Service Control Point on which an overlay process is loaded. The correct SCP is identified by the MGCF using a correlation identifier originally published by the SCP itself after having received an IN service trigger from an MSC or GMSC. The MGCF will receive call related data from the SCP, such as the original dialed number. This data is used by the MGCF to populate information elements in a SIP Invite message. WO 08075938 gives a solution for providing GSM specific information, e.g. dialed number, location information, to an IMS service.
There is a need in the art to enable efficient communication with a party operating in a hybrid network combining an Internet-protocol based network and a non-Internet-protocol based network, wherein communication allows calling the party using an addressing scheme usable in the non-Internet-protocol based network.